The present invention relates to an instrument feed stream processing device, e.g., an instrument probe that is used to separate certain components of a fluid and control the pressure of the fluid within the device and downstream instruments.
In the transport of fluids such as hydrocarbon gas, for example, natural gas, it is desirable to sample the gas to determine its properties. Such sampling can include the measurement of the Btu value of the gas. Even though natural gas is referred to as a gas, it oftentimes includes liquids and particulate matter. In order to ensure proper operation of some instruments, a pressure regulator and a filter/dryer are interposed in the flow path between the source of gas, e.g., a natural gas pipeline and the instrument. The pressure regulator and the filter dryer are separate units joined together by couplings and then coupled between the instrument and the conduit. Although effective in controlling pressure and eliminating deleterious material, there are a large number of joints as a result of such an arrangement of components with each joint providing a potential leakage source.
In addition to additional potential leak sources, each component is separately made usually from expensive materials, such as, stainless steel and aluminum alloys, increasing the cost of the total system. Separate units also utilize a large number of parts and/or assemblies.
An example of filter dryers include F-4 and F-23 from Welker Engineering, Co. of Sugar Land, Tex. Examples of pressure regulators are IR-4 and IRD-4SS also from Welker Engineering.
The deleterious materials, as discussed above, can include both liquid components and particulate matter. A liquid component could be detrimental, for example, if the instrument or instrument package includes a gas chromatograph. Liquid entering a gas chromatograph negatively affects its ability to perform an analysis and prevents the instrument from properly operating. It is thus desirable to separate liquid components from the natural gas and preferably exhaust those from the filter/dryer to prevent excessive accumulation. Also, particulate matter can negatively affect operation of an instrument by plugging small pores or flow channels. Thus, it is also desirable to preclude particulate matter of at least a certain size from entering the instrument. The filters to accomplish particulate separation arc well known in the art and examples are identified above. A filter for particulate matter generally accumulates the particulate material on the filter element or within the filter media The filter media is replaced or cleaned from time to time in order to ensure proper operation of the filter device and hence the downstream instrument.
The pressure in some natural gas pipelines can be very high, as high as 5,000 psi although typically the pressure in a pipeline is in the range of between about 300 psi and about 1200 psi gage pressure. It is desirable to reduce this pressure to a pressure in the range of between about 10 psi and about 50 psi prior to a sample entering the instrument and filter/dryer in order to protect both units and to permit the units to be constructed of elements that do not need to sustain the forces from high pressure.
As discussed, although there are commercially available devices to effect both pressure regulation and filtration/drying, there is a need for an improved device to effect both pressure regulation and filtering/drying.
The present invention involves the provision of a device for use in gathering and processing fluid samples from a conduit. The device includes a separator combined with a pressure regulator in a common housing. The housing has a body and a cap that are selectively separable. A coupler is provided for attaching the device to the conduit for the extraction of a sample therefrom and subsequent transmission to an instrument for evaluation. The housing includes a flow passage that includes an interior chamber in which is mounted a separator device operable to separate a gaseous component of the natural gas from other components of the natural gas. The separator device is positioned flow wise between an inlet and a first outlet that is adapted for connection to an instrument. A second outlet can be provided for the discharge of a separated liquid component from the housing. A valve is mounted to the housing and is positioned in the flow passage, flow wise between the inlet to the housing and the outlet to the instrument. The valve is operable to selectively prevent and permit flow of fluid to the outlet to the instrument from the inlet and is automatically opened and closed in response to pressure in a portion of the housing. The separator device can be of a replaceable or cleanable type and removable from the housing.